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Abstract

Aviptadil is an injectable formulation of vasoactive intestinal polypeptide (VIP) in combination with the adrenergic drug phentolamine. Aviptadil in combination with phentolamine and sexual stimulation, is expected to provide a new and effective alternative for erectile dysfunction (ED) patients that is essentially free of the troublesome side effects and cumbersome delivery methods which limit the use of other pharmacologic preparations. Aviptadil can be delivered using Senetek's novel and patented autoinjector (Reliaject), which renders the self-injection process exceptionally easy, unobtrusive to perform and helps ensure accurate, safe delivery of the medication [306380]. In July 1997, Senetek filed a PLA with the Danish Medicines Authority [253591] and its third PLA in Ireland for the treatment of moderate-to-severe, organic-based ED [255084]. In September 1997, Senetek filed PLAs seeking approval to market aviptadil in Switzerland, South Africa and New Zealand 1263505]; by April 2000, it had been approved in New Zealand [361039]. All clinical trials were placed on hold in August 1999 after the FDA advised the MCA of safety concerns regarding a competitor's phentolamine mesylate product (Vasomax; Zonagen Inc/Schering-Plough Corp). At this time, the activities to support the registration of aviptadil in the EU were ongoing and were not impacted by the clinical hold [336510]. In March 2000, after review by an independent clinical pharmacotoxicologist company employed by Senetek, the carcinogenicity observed in animal models was deemed to have no relevance as an indicator of carcinogenic risk in humans. This information was passed to the MCA along with an extensive review of all prior company studies and the medical literature supporting the efficacy and safety of phentolamine mesylate [361039]. In July 2000, the FDA upgraded the status of the aviptadil IND to a partial clinical hold, allowing human studies to be conducted in the US with a limited duration of 3 months and total number of doses not exceeding three per week. The FDA also recommended that Senetek conduct a two-year rodent study of aviptadil as a result of previously reported brown adipose tissue proliferations observed in the course of a competitor's rodent study in which phentolamine mesylate was administered daily [373086]. In August 2000, the MCA lifted the hold on trials stating the findings do not represent a significant carcinogenic risk in man [378615]. In October 2000, marketing approval in the UK was granted by the MCA. Regulatory filings in other European countries are underway to seek pan-European approval for aviptadil under the Mutual Recognition Process [385477].